1. Field of the Invention
The present invention relates to a rotary magnetic disc device and, in particular, to a rotary magnetic disc device which is suitable for use in a magnetic recording/reproducing apparatus in an electronic still camera or the like.
2. Description of the Prior Art
Recently, there has been developed an attractive electronic still camera system in which an image pickup device such as a solid image pickup element, an image pickup tube or the like is combined with a recording device. The recording device employs as a recording medium thereof an inexpensive magnetic disc having a relatively large storage capacity such that an object can be still photographed electronically and recorded on a rotating magnetic disc and the reproduction of the recorded image can be performed by means of a television system, a printer or the like which is provided separately from the electronic still camera system.
The magnetic disc that is used in such a camera system is usually in the form of a magnetic disc pack. In the magnetic disc pack there is rotatably stored a magnetic disc which is capable of magnetic recording of still image information or the like, and such magnetic disc pack is used after it is mounted to a rotary magnetic disc device which is incorporated in an electronic camera.
When the magnetic disc pack is mounted to the magnetic recording or reproducing apparatus in the electronic camera, it is troublesome and inconvenient to directly mount or locate a a central bore, which is formed in center core disposed in the central portion of the magnetic disc within the magnetic disc pack, onto a rotary drive shaft which is positioned on the side of the magnetic recording or reproducing apparatus. For this reason, such locating operation may result in the inaccurate mounting of the magnetic disc pack to the magnetic recording or reproducing apparatus.
In order to eliminate the above-mentioned problem, conventionally, there has been proposed a magnetic disc pack loading/unloading device which comprises a cover supported to the main body of the magnetic recording or reproducing apparatus such that it can be freely opened or closed, and a pack holder which can be operated cooperatively with the cover and in which the magnetic disc pack can be stored. In the magnetic disc pack loading/unloading device, by closing the cover after insertion of the magnetic disc pack into the pack holder, a magnetic disc in the magnetic disc pack within the pack holder can be mounted to the rotary drive shaft of the main body of the magnetic recording or reproducing apparatus.
In the above-mentioned magnetic disc pack loading/unloading device, there is provided a regulation plate on the opposite side of a magnetic head in order to locate the magnetic disc along the magnetic head during the magnetic recording or reproducing operation. This regulation plate is attached to a regulation plate holder provided in the cover so that it is spaced apart from the magnetic head when the cover is open while it is located at a position to face the magnetic head when the cover is closed. Such regulation plate must be defined accurately in the height and plane position thereof, and, therefore, there are erected from the side of the main body of the magnetic recording or reproducing apparatus height positioning pins for the regulation plate holder as well as plane position positioning pins for the regulation plate holder. These positioning pins can be brought into contact with the regulation plate holder or can be inserted into their corresponding positioning holes formed in the regulation plate holder, when the cover is closed, so as to determine the height and the position of the regulation plate holder accurately.
The above-mentioned regulation plate holder is formed larger in size than the magnetic disc pack and, as the height positioning pins thereof, there are provided a total of three pins arranged on the right and left of the magnetic disc pack (specifically, two pins on the recording/reproducing side of the magnetic disc pack and one on the opposite side thereof). Also, these three height positioning pins are adapted such that they are completely apart from the regulation plate holder when the cover is in the open state thereof.
As described above, the regulation plate holder used in the conventional rotary magnetic disc device is larger in size and the height positioning pins are long spaced from one another, which requires a higher rigidity, and thus the weight of the whole device is increased accordingly.
Also, due to the fact that the regulation plate holder is adapted such that it completely parts from the three height positioning pins, the regulation plate holder becomes loose too much. Further, when the cover is closed, after the regulation plate holder is brought into contact with the three height positioning pins, all of springs for energizing the regulation plate holder, which are located between the cover and the regulation plate holder correspondingly to the respective height positioning pins must be compressed. As a result of this, a great operation force is required to close the cover and when the cover is to be opened, the great operation force acts as a reaction force so that a large-size damper must be mounted.